1. Field of the Invention
This invention relates to an electroluminescent display device, particularly to a sealing structure of the electroluminescent display device.
2. Description of the Related Art
In recent years, electroluminescent (hereafter, referred to as an EL) display devices with EL elements have been receiving an attention as a display device substituting a CRT and an LCD.
Since the EL element is sensitive to moisture, there has been known an EL display panel structure in which the EL element is covered with a metal cap or a glass cap coated with a desiccant. FIG. 9 is a cross-sectional view showing such a conventional structure of the EL display panel.
A first glass substrate 70 has a display region formed with many EL elements 71 thereon. The first glass substrate 70 is attached to a second glass substrate 80 working as a cap with sealing resin 75 made of an epoxy resin. The second glass substrate 80 has a concave portion 81 (hereafter, referred to as a pocket portion 81) in a region corresponding to the above display region. The pocket portion 81 is coated with a desiccant layer 82 for absorbing moisture.
Here, the forming of the pocket portion 81 is for securing a space between the desiccant layer 82 and the EL element 71, thereby preventing the EL element 71 from being contacted by the desiccant layer 82, which may result in damaging the EL element 71.
As shown in FIG. 10, however, an external force can be applied to a surface of the first glass substrate 70. This can occur even in a manufacturing process of the EL display device (for example, a process of conveying a glass substrate) and also when a panel surface of the EL display device is touched by a user. This external force causes flexure in the first glass substrate 70, and the desiccant layer 82 and the EL element 71 contact each other. With the application of the further external force, the EL element 71 may be broken by stress from the desiccant layer 82. Furthermore, the same problems are caused by applying of the external force to a surface of the second glass substrate 80.